[PATCH 3.2 138/152] ACPI / EC: Fix regression due to conflicting firmware behavior between Samsung and Acer.

Ben Hutchings
2015-02-17T01:46:53Z

From: Lv Zheng <lv.zheng@intel.com>

commit 79149001105f18bd2285ada109f9229ea24a7571 upstream.

It is reported that Samsung laptops that need to poll events are broken by
the following commit:
Commit 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08
Subject: ACPI / EC: Add support to disallow QR_EC to be issued when SCI_EVT isn't set

The behaviors of the 2 vendor firmwares are conflict:
1. Acer: OSPM shouldn't issue QR_EC unless SCI_EVT is set, firmware
automatically sets SCI_EVT as long as there is event queued up.
2. Samsung: OSPM should issue QR_EC whatever SCI_EVT is set, firmware
returns 0 when there is no event queued up.

This patch is a quick fix to distinguish the behaviors to make Acer
behavior only effective for Acer EC firmware so that the breakages on
Samsung EC firmware can be avoided.

Fixes: 3afcf2ece453 (ACPI / EC: Add support to disallow QR_EC to be issued ...)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=44161
Reported-and-tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[ rjw : Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Kamal Mostafa <kamal@canonical.com>
---
drivers/acpi/ec.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)

--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -129,6 +129,7 @@ static int EC_FLAGS_MSI; /* Out-of-spec
static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
+static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */

/* --------------------------------------------------------------------------
Transaction Management
@@ -206,13 +207,8 @@ static bool advance_transaction(struct a
}
return wakeup;
} else {
- /*
- * There is firmware refusing to respond QR_EC when SCI_EVT
- * is not set, for which case, we complete the QR_EC
- * without issuing it to the firmware.
- * https://bugzilla.kernel.org/show_bug.cgi?id=86211
- */
- if (!(status & ACPI_EC_FLAG_SCI) &&
+ if (EC_FLAGS_QUERY_HANDSHAKE &&
+ !(status & ACPI_EC_FLAG_SCI) &&
(t->command == ACPI_EC_COMMAND_QUERY)) {
t->flags |= ACPI_EC_COMMAND_POLL;
t->rdata[t->ri++] = 0x00;
@@ -987,6 +983,18 @@ static int ec_enlarge_storm_threshold(co
}

/*
+ * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
+ * which case, we complete the QR_EC without issuing it to the firmware.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=86211
+ */
+static int ec_flag_query_handshake(const struct dmi_system_id *id)
+{
+ pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
+ EC_FLAGS_QUERY_HANDSHAKE = 1;
+ return 0;
+}
+
+/*
* On some hardware it is necessary to clear events accumulated by the EC during
* sleep. These ECs stop reporting GPEs until they are manually polled, if too
* many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
@@ -1052,6 +1060,9 @@ static struct dmi_system_id __initdata e
{
ec_clear_on_resume, "Samsung hardware", {
DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
+ {
+ ec_flag_query_handshake, "Acer hardware", {
+ DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
{},
};